Weird spot-tone effect

I have a print done on Bergger Neutral, developed in Dektol 1+2, HCA'd, washed,
dried, toned in Se 1+19 for 5 min, HCA'd, washed, and dried that has a couple
of white lines on it from some dust/threads that fell on the neg during
printing. One line was in the sky and the other was in a shadowed area. I
spotted in the very ligt sky without a problem but when I went to spot the line
in the dark region the white line turned reddish.

I was using the neutral black spot-tone dye (the usual almost-dry brush to pick
up dried dye and stipple technique) by itself. To test what was going on I
took some of it at full strength from the bottle and put it on a piece of
trimmed white border; that turned reddish too. Then I progressively diluted it
and still got a reddish color on the white border, but the intensity of the red
was proportional to the strength of the solution. Then I did the same thing
with the olive and blue dyes. Even full strength from the bottle they didn't
leave any trace of red on the white border.

Does anyone have any clue as to what is going on here and how I could spot out
this print?

TIA,
Curtis



CWal871581